Validators · 100% free
Email Preheader Length Checker
Check your preheader against Gmail, Apple Mail and Outlook truncation lengths.
Klaviyo Mailchimp Gmail Apple Mail Outlook
Gmail (desktop)
Last chance — 20% off your order ends tonight
Plus: free shipping on every order over $50 this week only.
59 / 85
Gmail (mobile)
Last chance — 20% off your order ends tonight
Plus: free shipping on every order over $50 this week only.
59 / 65
Apple Mail
Last chance — 20% off your order ends tonight
Plus: free shipping on every order over $50 this week only.
59 / 110
Outlook (desktop)
Last chance — 20% off your order ends tonight
Plus: free shipping on every order over $50 this …
59 / 50
Outlook (mobile)
Last chance — 20% off your order ends tonight
Plus: free shipping on every …
59 / 30
Yahoo Mail
Last chance — 20% off your order ends tonight
Plus: free shipping on every order over $50 this week only.
59 / 90
About this tool
Preheader (the preview text after the subject in inbox) is one of the highest-leverage and most-ignored email elements. Test against actual platform truncation: Gmail ~85 chars, Apple Mail ~110, Outlook ~50.
Preheader best practices
- • Make it complement, not repeat, the subject
- • First 30 chars matter most (Outlook mobile cuts there)
- • If empty, Gmail/Apple use the first body text — usually 'View in browser' or unsubscribe URL (terrible)
- • Use a hidden preheader span at the top of the email body
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